In a randomized clinical trail ICRF-187 was found to provide cardiac protection (as shown by changes in echocardiographic measurements, radionuclide studies and endomyocardial biopsies) against the development of doxorubicin-induced cardiomyopathy in patients with metastatic carcinoma of the breast. This protection was exerted without significant clinical side effects and without interfering with the effectiveness of the anti-neoplastic therapy. Thus, ICRF-187 is useful in extending the therapeutic effectiveness of doxorubicin.